Vulnerability · Published Aug 25, 2026 · Assigned by VulnCheck

CVE-2026-80199Kimai before 2.54.0 Username Enumeration via Timing Oracle

Low 3.7

In plain English

A low-severity security flaw in kimai from kimai. Proof-of-concept exploit code is public. The chance it is exploited in the next 30 days is estimated at 0.3% (higher than 24% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.

Severity (CVSS 3.1)3.7Low

Exploit odds (30 days)0.3%top 76.2% of all CVEs

Exploited in the wildNo reportsCISA SSVC: poc

Attack toolingNoneno public tooling known

Official description

Kimai before 2.54.0 contains a timing oracle vulnerability in TokenAuthenticator that allows unauthenticated attackers to enumerate valid usernames via X-AUTH-USER header. Attackers can measure response time differences when the password hasher runs only for existing users, enabling username enumeration with no login throttling protection.

Affected packages & fixed versions

Ecosystem	Package	Fixed in	Advisory
Packagist	kimai/kimai	2.54.0	GHSA-jrc6-fmhw-fpq2

Affected products (as reported)

Vendor	Product	Versions
kimai	kimai	0 – before 2.54.0

Weakness: CWE-208 · Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:N/A:N

References

GitHub Security Advisory (GHSA-jrc6-fmhw-fpq2) vendor-advisory
VulnCheck Advisory: Kimai before 2.54.0 Username Enumeration via Timing Oracle third-party-advisory